Numerous types of implantable medical devices (IMDs) are available for monitoring a patient and/or delivering automatic therapies, such as ECG monitors, cardiac monitors, pacemakers, defibrillators, drug delivery pumps, neurostimulators and the like. A general design goal in the manufacture of IMDs is to minimize the overall size of the IMD to promote patient comfort. Related to this goal is a desire to provide smooth exterior surfaces without sharp corners or edges that would cause patient discomfort. Additionally, it is desirable to minimize the cost and complexity of manufacturing steps used in producing IMDs.
The outer housing of the IMD encloses electronics that perform the various IMD functions such as acquiring and analyzing physiological signals, automatically delivering therapies, and wirelessly communicating with an external programmer or other device. As technological advances are made that may require additional circuitry or battery volume, efficient use of the volume enclosed by the IMD housing is important as the overall size of the IMD is reduced. The housing must also reliably shield internal electronics that could be damaged or malfunction if exposed to body fluids. A need remains for IMD housings and manufacturing methods that enable low cost manufacturing methods to be used without compromising the integrity of the housing as a shield against body fluids while still promoting patient comfort and facilitating overall IMD size reduction.